A possibility of KLOE-2 experiment to measure the width \(\varGamma_{\pi^{0} \to\gamma\gamma}\) and the π0γγ∗ form factor F(Q2) at low invariant masses of the virtual photon in the space-like region ...is considered. This measurement is an important test of the strong interaction dynamics at low energies. The feasibility is estimated on the basis of a Monte-Carlo simulation. The expected accuracy for \(\varGamma_{\pi^{0} \to\gamma\gamma}\) is at a per cent level, which is better than the current experimental world average and theory. The form factor will be measured for the first time at Q2≤0.1 GeV2 in the space-like region. The impact of these measurements on the accuracy of the pion-exchange contribution to the hadronic light-by-light scattering part of the anomalous magnetic moment of the muon is also discussed.
We present a detailed study, done in the framework of the INFN 2006 Roadmap, of the prospects for e+e- physics at the Frascati National Laboratories. The physics case for an e+e- collider running at ...high luminosity at the φ resonance energy and also reaching a maximum center of mass energy of 2.5 GeV is discussed, together with the specific aspects of a very high luminosity τ-charm factory. Subjects connected to kaon decay physics are not discussed here, being part of another INFN Roadmap working group. The significance of the project and the impact on INFN are also discussed. All the documentation related to the activities of the working group can be found in http://www.roma1.infn.it/people/bini/roadmap.html.
A feasibility test run for the MUonE project Ballerini, G.; Abbiendi, G.; Bonanomi, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2019, Volume:
936
Journal Article
Peer reviewed
Open access
The 3.4 σ discrepancy between the experimental value of the muon anomalous magnetic moment g-2 and the Standard Model prediction is one of the most intriguing indications of physics beyond the ...Standard Model. The MUonE project plans to measure the leading hadronic corrections to the muon g-2 by scattering high energy (∼150 GeV) muons off the atomic electrons of a low-Z target through the elastic process μ+e →μ+e. The angles of the incoming muons and the outcoming muons and electrons have to be measured precisely, to exploit the kinematical correlation of the μ-e collision. To reach this goal a modular target is foreseen, consisting of 60 low-Z (Be or C) elements, 1 cm thick, each sandwiched in layers of Si-microstrip detectors, organized in XY, XU and VY planes (±45 °, to disentangle double tracks). In 2018, a feasibility test at the CERN North Area is foreseen, running parasitically on the beamline behind COMPASS. The setup consist of 16 layers with an area of 9.5×9.5 cm2, 410μm thick, single side AGILE silicon detectors, which have a readout pitch of 242μm and a floating strip scheme, resulting in a position resolution of the order of 40μm. The DAQ rate is of the order of a few kHz. The contribution will describe the setup, the DAQ system and the first data collected during the commissioning phase in April/May.
The three precision measurements of the cross section σ(e+e− → π+π−γ(γ)) using initial state radiation by the KLOE collaboration provide an important input for the prediction of the hadronic ...contribution to the anomalous magnetic moment of the muon. These measurements are correlated for both statistical and systematic uncertainties and, therefore, the simultaneous use of these measurements requires covariance matrices that fully describe the correlations. We present the construction of these covariance matrices and use them to determine a combined KLOE measurement for σ(e+e− → π+π−γ(γ)). We find, from this combination, a two-pion contribution to the muon magnetic anomaly in the energy range 0.10 < s < 0.95 GeV2 of aμπ+π−=489.8±1.7stat±4.8sys×10−10.Data vectors and covariance matrices are available at http://www.lnf.infn.it/kloe/ppg/ppg_2017/ppg_2017.html.
THE ρ（770） S. Eidelman G. Venanzoni
中国物理C：英文版,
2016
10
Journal Article
Peer reviewed
The determination of the parameters of the ρ（770） is beset with many difficulties because of its large width. In physical region fits, the line shape does not correspond to a relativistic ...Breit-Wigner function with a P-wave width, but requires some additional shape parameter. This dependence on parameterization was demonstrated long ago 1. Bose-Einstein correlations are another source of shifts in the ρ（770） line shape, particularly in multiparticle final state systems 2.
The design of a rectangular waveguide 95 GHz (W-band) triplexer for ground radar systems is presented. The triplexer comprises three in-line filters, with inductive irises as coupling elements and a ...manifold formed by three T-junctions. In particular, the scheme proposed is aimed at handling large powers and reducing losses. The triplexer was assembled and measured, showing very good agreement with the simulated results.
In this paper, we describe how to define and build a set of known loads to be used in near-field microwave microscopy. Such loads are necessary to set up a microwave calibration kit, enabling local ...quantitative measurements by the microscope. The proposed protocol is validated through the microscopy system we have recently developed that combines a scanning tunneling microscope and a 70-GHz vector network analyzer.
The recent interest in a light gauge boson in the framework of an extra U(1) symmetry motivates searches in the mass range below 1 GeV. We present a search for such a particle, the dark photon, in ...e+e−→Uγ, U→π+π− based on 28 million e+e−→π+π−γ events collected at DAΦNE by the KLOE experiment. The π+π− production by initial-state radiation compensates for a loss of sensitivity of previous KLOE U→e+e−, μ+μ− searches due to the small branching ratios in the ρ–ω resonance region. We found no evidence for a signal and set a limit at 90% CL on the mixing strength between the photon and the dark photon, ε2, in the U mass range between 527 and 987MeV. Above 700 MeV this new limit is more stringent than previous ones.
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